Graphics cursors, which are also known under other names, such as "sprites", are now a common feature of display systems such as personal computers and the like. However, the provision of a graphics cursor is relatively expensive. This is because of the size of a graphics cursor and the high video rates of modern displays. Typically, a graphics cursor will be up to 64 pixels wide and 64 pixels high, with 2 bits required for each pixel. Thus, 1K bytes of storage are needed to store such a cursor. In order to refresh a display device with a video clock frequency of, say 50 MHz, the cursor data must be read at the rate of 2 bits every 20 nS, or 1 byte every 80 nS. This means that in prior art display systems, expensive, high speed RAM has had to be used for the storage of the data defining the cursor.